Traffic Light Simulator with Override to trigger a buzzer

[johnerrington]

The "traffic light" exercise is a very good contender for a state machine approach.
There are plenty of examples

Beginners: using the switch - case statement

Example 3: A SIMPLE state machine to show the traffic light sequence A single traffic light is a good example of a system that can have clearly defined states; and the switch construct makes it easy to see how this can be implemented as a state machine. Use the same arrangement of LEDs (see the fritzing) that you used in the first example. This code also introduces the ENUM type declaration, and a very easy way to understand millis() timing. At the start of each state we record the time "tim…

since its all non-blocking code you can add in the test for an input and compare with the
"timeElapsed" each time around the loop.